Display apparatus and its control method

ABSTRACT

The invention discloses an image display apparatus having a display device and a signal processing circuit for performing a signal processing according to a size of region of a predetermined color in an image to be displayed. The invention also discloses an image display apparatus having: a display device; and a signal processing circuit, wherein when a first image having a region to be displayed in a predetermined color and a predetermined brightness, that is, a first region in which a width in a predetermined direction is equal to a first value and a second image which is an image in which average luminance of a whole image is the same as that of the first image and which has a region to be displayed in the same color as the predetermined color and in the predetermined brightness, that is, a second region in which a width in the predetermined direction is larger than the first value are respectively displayed, the brightness of the first region in the first image is brighter than that of the second region in the second image by the signal processing in the signal processing circuit.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to an image display apparatus in which picturequality of a display image is improved.

2. Related Background Art

Hitherto, there are the following techniques to display an image of ahigh contrast ratio in a limited dynamic range.

The technique in which a whole display screen is divided into aplurality of regions and a video signal of each region is expandedindependent of video signals of the other regions and gamma (γ)corrected on the basis of distribution of a luminance value of the videosignal of the target region (for example, refer to JP-A No.2004-048185).

The technique in which a dynamic range is changed in accordance with anaverage luminance level in order to realize white peak characteristicslike a CRT (for example, refer to JP-A No. 2002-333858).

SUMMARY OF THE INVENTION

It is an object of the invention to realize an image display apparatuswhich can perform a preferable display or a manufacturing method of theimage display apparatus. According to embodiments, which will beexplained hereinafter, of the invention, constructional examples whichcan improve a contrast feeling, more specifically speaking, which canimprove a brightness feeling of a specific color region are shown.

The following examples can be mentioned as specific examples which canbe solved by the constructions of the embodiments, which will beexplained hereinafter, of the invention.

For example, in the conventional methods mentioned above,

according to the method whereby the region in the display screen isdivided and the video signal of the target region is expandedindependent of the video signals of the other regions and γ-corrected onthe basis of the distribution of the luminance value of the video signalof the target region, although the contrast feeling is improved ascompared with that in the case of γ-correcting in a lump in the wholedisplay screen, in the divided regions, a gain is still suppressed toone of a plurality of white peaks. Thus, there is a problem ofoccurrence of a portion which lacks the contrast feeling.

According to the method whereby the dynamic range is changed inaccordance with the average luminance level, since the gain isdetermined irrespective of an area, a width, and the like of the whitepeak, there is such a problem that the brightness feelings of white in aplurality of white peak portions are not adequately expressed.

One of the inventions regarding the invention is constructed as follows.That is,

an image display apparatus for displaying an image on the basis of imagedata, comprising:

detection means for detecting a size of color region of a predeterminedcolor on the basis of the image data; and

conversion means for converting the image data of the color region inaccordance with the size of the color region.

Another one of the inventions regarding the invention is constructed asfollows. That is,

an image display apparatus comprising:

a display device; and

a signal processing circuit for performing a signal processing accordingto a size of region of a predetermined color in an image to bedisplayed.

The size of region of the color is not limited to an area of such aregion but includes a size (width) in a predetermined direction. Theprocessing according to the size of region is not limited to aconstruction in which a processing amount (correction amount) is madedifferent in accordance with the size of region. For example, such aprocessing includes a construction in which although a specificprocessing is executed in the case of a predetermined size, the specificprocessing is not executed in the case of another size.

Still another one of the inventions regarding the invention isconstructed as follows. That is,

an image display apparatus comprising:

a display device; and

a signal processing circuit,

wherein (a) in at least one case where an image is displayed by a firstimage signal which designate a first image has a first region of apredetermined color and a predetermined brightness, the first region hasa first width in a predetermined direction, and

(b) in at least one case where an image is displayed by a second imagesignal which designate a second image, which is an image in whichaverage luminance of a whole image is the same as that of the firstimage, has a second region of the predetermined color and thepredetermined brightness, the second region has a second width largerthan the first width in the predetermined direction,

the brightness of the first region in the image which is displayed bythe first image signal is brighter than that of the second region in theimage which is displayed by the second image signal, by the signalprocessing in the signal processing circuit.

Preferably, the signal processing circuit has a conversion circuit forconverting image data on the basis of a control value according to thenumber of continuous pixels of the predetermined color.

According to the invention, in the display apparatus such as CRT, LCD,PDP, or the like, the contrast feeling and the brightness feeling can beimproved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram showing a rear projection type display apparatusaccording to the first embodiment of the invention;

FIG. 2 is a diagram showing a projection type display engine accordingto the first embodiment;

FIG. 3 is a block diagram of an image display apparatus according to thefirst embodiment;

FIG. 4 is a signal processing block diagram including a white peakcorrecting unit according to the first embodiment;

FIGS. 5A1, 5A2, 5A3, 5B1, 5B2 and 5B3 are explanatory diagrams forexplaining a white peak correcting method according to the firstembodiment; and

FIGS. 6A1, 6A2, 6A3, 6B1, 6B2 and 6B3 are explanatory diagrams forexplaining conventional correcting methods.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment

FIG. 1 is a side elevational view of a rear projection type displayapparatus 200 of the invention.

An image projected from a projection type display engine D1 is reflectedby a reflecting mirror 201 and projected from a rear surface of a screen6. A digitizer 202 is attached to a front surface of the screen 6.Position coordinates inputted by a pen 203 for the digitizer areinputted to the display apparatus 200 from the front surface of thescreen 6. A digitizer of an optical type, a pressure sensitive type, anultrasonic wave type, or the like can be used as a digitizer 202.

A brightness adjusting switch (SW) 204 is a switch to instruct thebrightness of a display screen.

According to the projection type display engine D1 in FIG. 2, threeliquid crystal panels 2R, 2G, and 2B corresponding to color displays ofR, G, and B are used as light modulating devices (display devices). Thethree liquid crystal panels 2R, 2G, and 2B are arranged at positionswhich face surfaces of a cross prism 7. The following panels can be usedas liquid crystal panels 2R, 2G, and 2B: a TN (Twisted Nematic) typeliquid crystal panels of an active matrix type which are driven by usingTFTs; ferroelectric liquid crystal panels of the active matrix typewhich can execute the high-speed operation; OCB (Optically CompensatedBend) liquid crystal panels; or the like. Polarizing plates 8 arearranged on both sides of each of the liquid crystal panels 2R, 2G, and2B so as to sandwich each panel, respectively. A projecting lens 9 andthe screen (member to be projected) 6 are arranged on the light outgoingside of the cross prism 7.

A parabolic reflector 10 is arranged so as to surround a lamp (lightsource) 1, thereby allowing emission light from the lamp 1 to beconverted into a parallel light beam. The reflector 10 is not limited tothe parabolic shape but may be formed in an elliptic shape so as toconvert the incident light into a converging light beam. A metal halidelamp, a xenon lamp, or the like can be used as a lamp 1.

Integrators 40 and 41 of the fly's eye are arranged on an optical pathof the light emitted from the lamp 1 so as to have a conjugate relationwith the liquid crystal panels 2R, 2G, and 2B and unevenness of thelight source is improved.

A relay lens 11 and a mirror 12 are sequentially arranged on the lightoutgoing side of the fly's eye integrators 40 and 41. Further, twodichloic mirrors 13 and 14 are arranged, thereby branching the emissionlight from the lamp 1 into three kinds of light. A relay lens 15 andmirrors 16, 17, and 18 are arranged, thereby guiding the branched lightto the liquid crystal panels 2R, 2G, and 2B, respectively. Referencenumeral 19 denotes a field lens.

Processes of an electric signal in the projection type display engine ofthe embodiment will now be described. FIG. 3 is a block diagram of theembodiment according to the invention.

A video signal which is outputted from a personal computer (PC) 300 anda television (TV) signal demodulated from a broadcasting wave areinputted to video signal processing means 3 through a PC input 50 and anNTSC input 51 and either the video signal or the TV signal is selectedby a switch 30. The selected image signal is transmitted to a peakcorrecting unit 103 through an A/D converter 31, a DSP 32, and aresolution converter 101. A memory 33 stores present image data andimage data of a next frame. The peak-corrected image data is convertedinto an analog signal by a D/A converter 35 and inputted to a paneldriver 36. The panel driver 36 supplies driving signals based on theimage data to the liquid crystal panels 2R, 2G, and 2B, respectively.

In the DSP unit 32, display image processes such as contrast adjustment,brightness adjustment, color conversion, and the like are executed.

Although only an analog input signal is shown in this block diagram, theinvention is not limited to it but, naturally, the invention is alsoeffectively applied to a construction in which an input terminal ofLVDS, TMDS, or the like, a D4 terminal for a digital television, or thelike is provided.

A signal processing circuit 52 executes signal processes such asdecoding of the NTSC signal, noise reducing process, band limitationfiltering, signal level adjustment, and the like.

A ballast 57 is a lamp power source connected to the lamp 1. A systempower source 58 supplies an electric power to the whole system from anAC inlet 60. A remote control 61 is a device which is used for the userto execute various operations of the display apparatus. A control panel62 receives a signal which is transmitted from the remote control 61.

A brightness adjusting switch detecting unit 109 detects the operationof the brightness adjusting switch 204. A digitizer detecting unit 118detects the coordinates designated by the digitizer 202.

A CPU 63 is connected to the foregoing video signal processing means 3,control panel 62, ballast 57, brightness adjusting switch detecting unit109, digitizer detecting unit 118, a USB I/F 107, and the like. The CPU63 controls the driving of the liquid crystal panels 2R, 2G, and 2B, thelamp 1, and the like and executes processes such as enlargement,reduction, and movement of the display image.

Although the embodiment has been described on the assumption that thebrightness adjusting switch detecting unit 109, digitizer detecting unit118, USB I/F 107, and the like are connected to the CPU 63, they can bealso constructed in such a manner that they are built in the CPU orexecuted by a program.

The PC 300 comprises: a CPU 301; an HD (hard disk) 302; a RAM 303; a ROM304; a video memory 305; a graphic controller 306; a mouse I/F 307; aUSB I/F 308; and the like. The PC 300 has a video output terminal 309, aUSB input terminal 310, and a mouse input terminal 311. A mouse 312 isconnected to the mouse input terminal 311.

A principle of the white peak correction according to the embodimentwill now be described with reference to FIGS. 5 and 6.

FIGS. 6A1, 6A2, 6A3, 6B1, 6B2 and 6B3 show examples of conventionaldynamic range improving correction. FIGS. 6A1, 6A2 and 6A3 show displayexamples before the correction. FIGS. 6B1, 6B2 and 6B3 show displayexamples after the correction corresponding to the display examples ofFIGS. 6A1, 6A2 and 6A3. An axis of ordinate indicates display luminanceand an axis of abscissa indicates a position in the horizontaldirection. A broken line shows an average luminance level (APL) of eachdisplay example, as shown in the conventional examples of FIGS. 6A1, 6A2and 6B3, in the case of executing a process to change the dynamic rangeof the display in accordance only with the average luminance, when theaverage luminance level is low as shown in FIG. 6A 1, the contrast canbe improved by increasing a gain of the white peak as shown in FIG. 6B1. On the contrary, when the average luminance level is high as shown inFIG. 6A 2, the gain is not changed and the contrast can be improved inaccordance with a size of white region. However, in the case of FIG. 6A3, since the average luminance is equal to that in FIG. 6A 2, thecontrast is not improved in spite of the white peak of a narrow region.

On the other hand, according to the invention, since the apparatus hasthe detection means for detecting the size of white region, a gradationis changed in accordance with the size of white region.

FIGS. 5A1, 5A2, 5A3, 5B1, 5B2 and 5B3 show examples of dynamic rangeimproving correction according to the invention. FIGS. 5A1, 5A2 and 5A3show display examples before the correction. FIGS. 5B1, 5B2 and 5B3 showdisplay examples after the correction corresponding to the displayexamples of FIGS. 5A1, 5A2 and 5A3. When the white region is narrow asshown in FIGS. 5A1 and 5A3, a process for raising the gain of the whitepeak is executed irrespective of the average luminance level (APL). Asshown in FIG. 5A 2, when the white region is wide, the process in whichthe gain is not changed is executed in a manner similar to theconventional example.

FIG. 4 is a block diagram showing details of the white peak correctingunit 103.

A peak detecting unit 401 detects the white peak from a threshold valueand an area of white region. The threshold value is determined from ahistogram of the image data to be displayed or an average luminance.

A peak correction control unit 402 controls a gradation control unit 403and a white balance controlling unit 404 in accordance with the size ofwhite portion detected by the peak detecting unit 401.

The gradation control unit 403 converts the image data so as to increasethe image data of the white peak portion determined to be the white peakby the peak detecting unit 401 in accordance with the magnitude of thewhite peak.

If the luminance has already reached the maximum value, displayluminance is further raised by changing the white balance by the whitebalance controlling unit 404. In a color diffusion unit 405, when thewhite balance is changed from a predetermined white balance by the whitebalance controlling unit 404, the color corresponding to the shiftamount from the predetermined white balance is diffused to a peripheralregion.

In a V-T correcting unit 406, correction of a V-T curve is made inaccordance with the characteristics of the liquid crystal panels.

Explanation will be made in detail hereinbelow.

The peak detecting unit 401 detects a ratio of the video signals R, G,and B of each of the inputted pixels, there by discriminating whether ornot the color of the pixel is an achromatic color. In this example, thepixel which is formed by the signals R, G, and B whose ratio is equal toor less than 5% (in other words, a difference between a value of thesignal having the maximum value and a value of the signal having theminimum value among the signals R, G, and B to form one pixel is equalto or less than 5% of the maximum value) is handled as an achromaticpixel. Subsequently, whether or not the signal of the pixel determinedto be achromatic becomes a target to be subjected to the white peakprocess is decided. A luminance level is compared with the averageluminance level (APL) of the input video signal and the pixel whoseluminance level is higher than the APL is set to the target pixel of thewhite peak process. That is, among the achromatic pixels, the pixelwhose luminance level is higher than the APL is handled as a pixel of apredetermined color (white in this embodiment). The number of continuoustarget pixels of the white peak process is counted. The white peakprocess is controlled in accordance with a count value indicative of thesize of white region.

In the embodiment, the white peak process is executed when a countnumber Kw of the white peak target pixels is equal to or less than 20.Assuming that the luminance level of white is increased by 10% when Kw=1and it is set to the value of 1 time when Kw=21, arithmetic operationsfor the white peak process are as follows.Rout={1+f(Kw)}·RinGout={1+f(Kw)}·GinBout={1+f(Kw)}·Binwheref(Kw)=(20−(Kw−1))/200{1+f(Kw)} denotes a gain

In the embodiment, the luminance level has been set in such a mannerthat a white peak increase amount changes linearly when the count numberKw of the white peak target pixels is equal to or less than 20. However,by changing the above function f(Kw) in accordance with thecharacteristics of the display device or a video scene to be displayed,the white peak correction which is optimum to the display device or thevideo scene can be made. Although the value of 20 pixels has been usedhere as a threshold value which is used to discriminate whether or notthe peak process is executed, such a value can be properly set. A valuewhich is equal to or less than 5% of the total number of pixels in apredetermined direction (horizontal direction here) is preferably used.In this constructional example, kw is inputted as a control value intoan arithmetic operating circuit for the white peak process. When thecount value is equal to or larger than 22, the foregoing correctingprocess is not executed in the arithmetic operating circuit for thewhite peak process. Particularly, in this embodiment, the apparatus isconstructed so that a degree of correction can be adjusted in accordancewith the count value Kw. It is also possible to construct the apparatusin such a manner that the control value is generated only either in thecase where the count value (for example, 1 or 0) is equal to or lessthan (is less than) a predetermined value or in the case where it islarger than the predetermined value (is equal to or larger than thepredetermined value) or and the uniform correction is made in accordancewith the presence or absence of the control value.

The embodiment has been described with respect to the example in whichthe number of white pixels in the horizontal direction is counted andthe white peak correction is made. By this method, the correctionaccording to the size (width) of white region in the horizontaldirection can be made. Specifically speaking, the following control canbe made with respect to the case where the first and second images whoseAPLs are set to the same value. The following case is mentioned here asan example: the first image has a region which is a white region to bedisplayed at the predetermined luminance and in which the width in thehorizontal direction is equal to or less than a predetermined width (20pixels here) and the second image has a region which is a white regionto be displayed at the same luminance as the predetermined luminance andin which the width in the horizontal direction is larger than thepredetermined width. In the image actually displayed in this instance,the luminance is controlled so that the luminance of the region of thefirst image is brighter than that of the region of the second image. Anexpression that one luminance is brighter than the other one denotes arelative relation. That is, by controlling so that the luminance of theregion of the second image is darkened, control can be made so that theluminance of the region of the first image is felt bright as a relativefeeling.

By providing a plurality of line memories and counting the number ofpixels in the vertical direction, the white peak correction in thevertical direction can be made.

By deciding the size of white region on the basis of the count number ofthe white peak pixels in the horizontal direction and the count numberof the white peak pixels in the vertical direction and by determiningthe white peak correction amount on the basis of the size of whiteregion obtained two-dimensionally, the white peak correction can be mademore effectively.

The operation of the white balance controlling unit 404 and the colordiffusion unit 405 will now be described.

Generally, in many display apparatuses, the white balance can bechanged. There is a display apparatus which can change a colortemperature to a value within a range from a low color temperature ofabout 6500° to a high color temperature of about 9500°. Further, thereis a display apparatus in which the user can adjust the colortemperature every 500°, or the like.

The adjustment of the color temperature is made by changing the gain ofthe signal level which is given to each of the RGB panels.

For example, when R:G:B=1:1:1 at 6500°, since it is necessary to set ahue to be bluish in order to obtain 9500°, by reducing the gains of Rand G, the ratio (R:G:B) is changed to R:G:B=8:8:10.

Therefore, since the gains of R and G are reduced, the luminance islower than that in the case where the image signals of R and G of 100%are outputted. Accordingly, if the white balance has been adjusted, theluminance of the display apparatus is set to be lower than the luminancewhich can be inherently displayed.

The display apparatus which can output the maximum luminance when thepixel values are equal to (R, G, B)=(100, 100, 100) are adjusted to (R,G, B)=(80, 80, 100) in a gain control unit in order to adjust the whitebalance. If each of the RGB signals is increased by 10% in the whitepeak state, (R, G, B)=(88, 88, 100) and the pixel value of B is maximum,so that the luminance cannot be raised. Therefore, the white balance isdeviated from the set value.

When the white peak exists in a small region, it is difficult toperceive a color drift. However, if there are a plurality of white peaksor if a deviation amount of the white balance is large, there is also acase where a problem occurs.

Therefore, by diffusing the deviation amount of the white balance to theperipheral pixels by the color diffusion unit 405, the white balances ofa plurality of pixel regions are equalized. In the above embodiment,since each of the R and G pixel values is deviated by 8, the valuesobtained by subtracting 2 from each of the four upper, lower, right, andleft pixels are displayed, thereby substantially equalizing the whitebalances of a plurality of pixel regions.

Consequently, the white peak of the brightness higher than the luminancerestricted by the white balance and the display apparatus of higherpicture quality can be provided.

Second Embodiment

The example in which the white region is detected and the white peakprocess is executed has been shown in the embodiment 1. The secondembodiment will now be described with respect to a method whereby thepeak process of a predetermined specific color is executed and a clearimage is obtained.

In many projection type display apparatuses, generally, importance isattached to light using efficiency and a high pressure mercury lamp isused as a light source. However, the high pressure mercury lamp has sucha tendency that the luminance of the red region is low due to spectrumcharacteristics of the lamp.

Therefore, hitherto, for example, an amount of transmission light isincreased by widening a cutting wavelength of a filter of the dichloicmirror 14 for red color separation. However, although the luminance ofred increases, purity of chromaticity of red deteriorates and a colorgamut is narrowed.

According to the invention, by detecting the size of red region andexecuting the peak correcting process in accordance with this size, theclear image can be displayed even in the red region without narrowingthe color gamut of red like conventional apparatus.

The peak process for red in the embodiment will now be described withreference to FIGS. 3 and 4 again. It differs from the first embodimentwith respect to a point that the peak correcting unit 103, peakdetecting unit 401, and peak correction control unit 402 execute thepeak correcting process to red as a predetermined color.

The peak detecting unit 401 detects the ratio of the R, G, and B signalsof the input video signal, thereby discriminating whether or not thesignal is red. In this embodiment, the signal in which each of the G andB signals is equal to or less than 5% of the R signal is determined tobe red. Subsequently, whether or not the peak process is executed to thesignal determined to be red is discriminated. For this purpose, thenumber of continuous peak process target pixels of red is counted andthe peak process is controlled in accordance with a count value.

In the embodiment, the peak process is executed when a count number Krof the peak target pixels of red is equal to or less than 20. Assumingthat the red luminance is increased by 10% when Kr=1 and is set to thevalue of 1 time when Kr=21,Rout={1+f(Kr)}·RinGout=GinBout=Binwheref(Kr)=(20−(Kr−1))/200{1+f(Kr)} denotes a gain

In a manner similar to the first embodiment, according to the secondembodiment, the apparatus is set in such a manner that when the countnumber Kr of the peak target pixels of red is equal to or less than 20,an increase amount of the red peak linearly changes. However, bychanging a function f(Kr) in the equation in accordance with thecharacteristics of the display device or the video scene to bedisplayed, the red peak correction which is optimum to the displaydevice or the video scene can be made.

Also in this embodiment, with respect to the deciding method of the sizeof red region and the white balance adjusting method, methods similar tothose in the first embodiment can be used.

For example, the image signal whose pixel values are equal to (R, G,B)=(80, 0, 0) is determined to be a red peak correction target image.Assuming that the R signal is increased by 10%, (R, G, B)=(88, 0, 0) andthe white balance controlling unit 404 is adjusted so as to output the Rsignal exceeding the restriction value due to the white balance.

In the case where the pixel values have been adjusted so that (R, G,B)=(100, 80, 80) are set to the maximum value by the white balance, ifthe R signal (R, G, B)=(100, 0, 0) is inputted, since the value of R isthe maximum value, the luminance of R cannot be increased. In thismanner, when the R signal has the maximum value, the peak correctingprocess for increasing the luminance of red by increasing the G or Bsignal and, for example, by increasing each of the G and B signals by 5%like (R, G, B)=(100, 5, 5) is executed.

Such a process is executed by using human sensory characteristics inwhich it is difficult to perceive the color drift because the red peakexists in the small region.

Consequently, the red peak of the brightness which is equal to or higherthan the luminance restricted by the white balance can be expressed andthe display apparatus of a clear image of high picture quality can beprovided.

As described above, in the invention, by changing the image data of thered region in accordance with the size of red region, the lack ofcontrast feeling of red and the lack of brightness feeling which arecaused by the lack of luminance of red as a problem mentioned above canbe also corrected. Further, the display apparatus which can display aclear image of high picture quality can be provided.

Although the example in which the peak process is executed to red hasbeen described in the embodiment, naturally, the invention can be alsoapplied to another color.

This application claims priority from Japanese Patent Application Nos.2005-007481 filed on Jan. 14, 2005 and 2005-372527 filed on Dec. 26,2005, which are hereby incorporated by reference herein.

1. An image display apparatus for displaying an image on the basis ofimage data, comprising: detection means for detecting a size of colorregion of a predetermined color on the basis of said image data; andconversion means for converting the image data of said color region inaccordance with the size of said color region.
 2. An apparatus accordingto claim 1, wherein the color region of said predetermined color is awhite region.
 3. An apparatus according to claim 1, wherein saidconversion means for converting said image data is control means forcontrolling a gradation.
 4. An apparatus according to claim 2, whereinsaid detection means for detecting the size of said color region iscounter means for counting the number of continuous pixels in which saidimage data is a white peak.
 5. An apparatus according to claim 2,further comprising white balance control means for changing a whitebalance in accordance with the size of said white region.
 6. Anapparatus according to claim 5, further comprising color diffusion meansfor diffusing the color to a peripheral pixel in accordance with achange in said white balance.
 7. An apparatus according to claim 6,wherein said color diffusion means changes a pixel value of theperipheral pixel by a change amount of the pixel value according to thechange in said white balance.
 8. An image display apparatus comprising:a display device; and a signal processing circuit for performing asignal processing according to a size of region of a predetermined colorin an image to be displayed.
 9. An image display apparatus comprising: adisplay device; and a signal processing circuit, wherein (a) in at leastone case where an image is displayed by a first image signal whichdesignate a first image has a first region of a predetermined color anda predetermined brightness, the first region has a first width in apredetermined direction, and (b) in at least one case where an image isdisplayed by a second image signal which designate a second image, whichis an image in which average luminance of a whole image is the same asthat of said first image, has a second region of the predetermined colorand the predetermined brightness, the second region has a second widthlarger than the first width in the predetermined direction, thebrightness of said first region in said image which is displayed by saidfirst image signal is brighter than that of said second region in saidimage which is displayed by said second image signal, by the signalprocessing in said signal processing circuit.
 10. An apparatus accordingto claim 9, further comprising a converting circuit for converting imagedata on the basis of a control value according to the number of pixelsof said predetermined color which are continuous in said predetermineddirection.
 11. A control method of an image display apparatus fordisplaying an image on the basis of image data, comprising the steps of:detecting a size of color region of a predetermined color on the basisof said image data; and converting the image data of said color regionin accordance with the size of said color region.